Synthesis, crystal structure and applications of palladium thiosalicylate complexes

AbstractThree palladium thiosalicylate complexes [Pd(tb)(bipy)]·3H2O (1), [Pd2(tb)2(bipy)2]·(dtdb)2 (2) and [Pd2(tb)2(phen)2]·dtdb·H2O (3) (bipy=bipyridine; phen=phenanthroline) were prepared from the reaction of PdCl2(CH3CN)2 with dithiosalicylic acid (dtdb) which underwent cleavage to form thiobenzoate anion (tb) in DMF/MeOH. Square planar geometries of the complexes with a N2SO coordination type were proposed on the basis of single crystal X-ray structural study. The presence of trapped and uncoordinated dtdb was observed in complexes 2 and 3. Complexes 1–3 were evaluated as catalysts for Heck coupling reactions of methyl acrylate with iodobenzene, and showed moderate activities at a very low catalyst loading. Complex 1 was found to inhibit the growth of bacteria and scavenge free radicals efficiently

Nutritional and Biological Evaluation of Leaves of Mangifera indica from Mauritius

Mango trees are evergreen plants that are present all around Mauritius. In this study, mango leaves, Mangifera indica grown in Mauritius were investigated for their nutritional values involving proximate composition, total flavonoid (TFC), total phenolic (TPC), and mineral content, and phytochemicals as well as its antioxidant and antibacterial properties. The ash, crude fat, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) of the mango leaves were found to be 12.61, 3.92, 35.32, 34.98, and 12.86%, respectively. The calcium content (2.15%) was above the normal required range, while the phosphorus content (0.12%) and crude protein content (13.60%) were within the normal required range of common fodders. The phytochemical results showed the presence of saponins, alkaloids, phenols, tannins, and flavonoids in the crude, EtOAC, and MeOH extracts. The values of TPC and TFC were higher for the EtOAC extract compared to the MeOH extract. Several secondary metabolites were identified from the leaves of the Mangifera indica which include 11 phenols, 4 xanthones, 9 flavanols, 10 benzophenones, 7 terpenoids, and 4 derivatives of gallotannins using UPLC-MS/MS. The presence of these metabolites is responsible for good antioxidant and antibacterial properties. Hence, mango leaves can be exploited for its potential use as a supplementary fodder for ruminants

The use of optically active O-alkyl ester hydrochlorides of L-phenylalanine and L-tyrosine as chiral micellar media for the catalysis of diels-alder reactions

The effect of a range of O-alkyl ester hydrochloride surfactants derived from L-phenylalanine and L-tyrosine as catalysts on the Diels-Alder reaction between cyclopentadiene and methyl acrylate was studied. Both chain lengths (C8-C14) and head groups of the surfactants were found to influence the yield and selectivity of the Diels-Alder product. The C10 derivatives of both phenylalanine and tyrosine surfactants gave the highest yields and selectivity. Phenylalanine ester hydrochlorides showed better catalytic activity than the tyrosine derivatives. Adduct optimum yield was obtained at a concentration relating to their critical micelle concentration (CMC) values. The Diels-Alder reaction was also found to be favored in acidic condition (pH 3) as well as in the presence of lithium chloride (LiCl) as salting out agent

Synthesis and anti-HIV activity of novel macrocyclic benzamides with a disulphide bridge

842-846A series of macrocyclic dilactams containing a disulphide bridge has been synthesized by the condensation of 2,2'-dithiodibenzoyl chloride with diamines. These compounds have been evaluated for their ability to inhibit reverse transcriptase (RT) of the human immunodeficiency virus HIV-1 (IIIB) and HIV-2 (ROD) in acutely infected MT-4 cells. The anti-HIV activity of these compounds depends on the ring size and also on the diamino counterpart. The dilactams with 12-membered rings 1 and 5 were found to be the most potent. The active analogues 1 and 5 inhibit the replication of HIV-1 (IIIB) and HIV-2 (ROD) with an EC50 between 1.2 to 4.4 μg/mL. The dilactam 7 shows comparable activity in C8166 cells

Structure-activity relationship of Schiff base derivatives of bis(aminophenyl)disulfide and p-vanillin as antimicrobial agents

A series of Schiff bases (1-9) were assayed for antibacterial (S. aureus, E. faecalis P. aeruginosa) and antifungal (C. albicans and A. niger) activities using disc diffusion method. Among the compounds tested [bis(p-methoxybenzaldimino)phenyldisulfide], 5 showed the most favourable antibacterial and [o,o'-(N,Ndipicolinyldene) diazadiphenyldisulfide], 6 antifungal activities with MICs of 1 mg/mL and 0.025 mg/mL against S. aureus and C. albicans respectively.© 2010 International Formulae Group. All rights reserved.Keywords: Antibacterial activity, antifungal, Schiff bases, disulfide

Synthesis, biological and catalytic properties of Ru(II) benzamides Schiff base complexes

2536-2540A few Schiff bases (p-chlorobenzaldehyde)-benzylimine 1, (salicylaldehyde)-p-toluidiimine 2, bis(p-anisaldehyde)ethylenediimine 3, bis(1-naphthaldehyde)-p-phenylenediimine 4, bis(m-nitrobenzaldehyde)-p-phenylenediimine 5, and bis(salicylaldehyde)-o-phenylenediimine 6 have been synthesized and reacted with RU2Cl2(DNBH)(H2O)4 (TR1) to yield six binuclear ruthenium complexes 1a-6a. All the complexes are characterized by spectroscopic, elemental and magnetic susceptibility data. The coordination is found to be through carbonyl oxygen of amide, phenolic oxygen and azomethine nitrogen of the Schiff bases in the octahedral environment of the metal. All the metal complexes show antibacterial and catalytic activity

Synthesis of Cyclo (L-Trans-(4-Hydroxyprolinyl)-L-Phenylalanine)

The diketopiperazine Cyclo (L-trans-(4-Hydroxyprolinyl)-L-phenylalanine)1 has been synthesized by coupling a  suitably protected form of L-trans-hydroxy proline with L-phenylalanine ethyl ester, deprotection of the amino group followed by an deacetimisation and finally desilylation. This final product has spectral data that agree with the already reported data in literature.Keywords: diketopiperazine, hydroxyproline, phenylalanin

Slow diffusion in situ ruthenium/ligand reaction: crystal structures, fluorescence and biological properties

Promoted by RuCl3·3H2O coordination in the mixed solvent DMF/H2O, diverse in situ S–S bond reactions such as S–S bond scission and S-oxidation occurred in the disulfide ligand of 2,2?-dithiodibenzoic acid (dtdb) to yield the new sulfinato-benzoate ligand (sb). The X-ray analysis of complexes of [Ru(phen)2(sb)] (1) and [Ru(bipy)2(sb)·H2O] (2) revealed that in both complexes, the ruthenium ion was found to be in an octahedral geometry, coordinating to the sulfur atom, rather than the oxygen of sulfinate. The complexes were found to be active against the bacterial strains tested with MIC ranging from 14.3–261 ?M. In addition, the metal complexes present strong DNA binding affinity constants in the major or minor grooves at the order of magnitude 105-106 M? 1. The antioxidant activities of the ligand and its metal complexes were investigated through scavenging effects for DPPH in vitro, indicating that the compounds show stronger activities than some standard antioxidants, such as ascorbic and vitamin C